Abnormal CTLA-4 function in T cells from patients with systemic lupus erythematosus

CTLA-4 is a critical gatekeeper of T-cell activation and immunological tolerance and has been implicated in patients with a variety of autoimmune diseases through genetic association. Since T cells from patients with the autoimmune disease systemic lupus erythematosus (SLE) display a characteristic hyperactive phenotype, we investigated the function of CTLA-4 in SLE. Our results reveal increased CTLA-4 expression in FOXP3(-) responder T cells from patients with SLE compared with other autoimmune rheumatic diseases and healthy controls. However, CTLA-4 was unable to regulate T-cell proliferation, lipid microdomain formation and phosphorylation of TCR-zeta following CD3/CD28 co-stimulation, in contrast to healthy T cells. Although lupus T cells responded in vitro to CD3/CD28 co-stimulation, there was no parallel increase in CTLA-4 expression, which would normally provide a break on T-cell proliferation. These defects were associated with exclusion of CTLA-4 from lipid microdomains providing an anatomical basis for its loss of function. Collectively our data identify CTLA-4 dysfunction as a potential cause for abnormal T-cell activation in patients with SLE, which could be targeted for therapy.

CD19(+)CD24(hi)CD38(hi) B cells exhibit regulatory capacity in healthy individuals but are functionally impaired in systemic Lupus Erythematosus patients

The immunosuppressive function of regulatory B cells has been shown in several murine models of chronic inflammation, including collagen-induced arthritis, inflammatory bowel disease, and experimental autoimmune encephalomyelitis. Despite interest in these cells, their relevance to the maintenance of peripheral tolerance in humans remains elusive. Here, we demonstrate that human CD19(+)CD24(hi)CD38(hi) B cells possessed regulatory capacity. After CD40 stimulation, CD19(+)CD24(hi)CD38(hi) B cells suppressed the differentiation of T helper 1 cells, partially via the provision of interleukin-10 (IL-10), but not transforming growth factor-beta (TGF-beta), and their suppressive capacity was reversed by the addition of CD80 and CD86 mAbs. In addition, CD19(+)CD24(hi)CD38(hi) SLE B cells isolated from the peripheral blood of systemic lupus erythematosus (SLE) patients were refractory to further CD40 stimulation, produced less IL-10, and lacked the suppressive capacity of their healthy counterparts. Altered cellular function within this compartment may impact effector immune responses in SLE and other autoimmune disorders.

Is there a feudal hierarchy amongst regulatory immune cells? More than just Tregs

Nature has provided the developing immune system with several checkpoints important for the maintenance of tolerance and the prevention of autoimmunity. The regulatory mechanisms operating in the periphery of the system are mediated by subsets of regulatory cells, now considered principal contributors to peripheral tolerance. Regulatory T cells (Tregs) have received titanic interest in the past decade, placing them at the centre of immuno-suppressive reactions. However, it has become clearer that other immune suppressive cells inhibit auto-reactivity as effectively as Tregs. The function of Tregs and other regulatory cells in rheumatoid arthritis will be discussed in this review.

Selective targeting of B cells with agonistic anti-CD40 is an efficacious strategy for the generation of induced regulatory T2-like B cells and for the suppression of lupus in MRL/lpr mice

We have previously reported that IL-10(+) regulatory B cells, known to play an important role in controlling autoimmunity and inflammatory disorders, are contained within the transitional 2 immature (T2) B cell pool (T2 Bregs). Therapeutic strategies facilitating their enrichment or enhancing their suppressive activity are highly attractive. In this study, we report that agonistic anti-CD40 specifically targets T2 B cells and enriches Bregs upon short-term in vitro culture. Although transfer of unmanipulated T2 B cells, isolated from mice with established lupus, failed to confer protection to diseased mice, transfer of in vitro anti-CD40-generated T2 B cells (T2-like-Bregs) significantly improved renal disease and survival by an IL-10-dependent mechanism. T2-like-Bregs readily accumulated in the spleen after transfer, suppressed Th1 responses, induced the differentiation of IL-10(+)CD4(+)T cells, and conveyed a regulatory effect to CD4(+)T cells. In addition, in vivo administration of agonistic anti-CD40, currently on trial for the treatment of cancer, halted and reversed established lupus. Taken together, our results suggest a novel cellular approach for the amelioration of experimental lupus.

Magnetic resonance imaging and ultrasonography in predicting pathologic extent after preoperative chemotherapy in stage II-III breast cancer

Abstract #4024

Introduction and aims: the main advantage of preoperative chemotherapy (PCT) is tumor down-staging, that can allow either mastectomy in large, inoperable primaries, or breast conserving surgery (BCS) for patients initially candidate to mastectomy. Therefore, an accurate measurement of residual disease after PCT is critical in the optimal surgical planning. Aim of this study is to evaluate the accuracy of breast magnetic resonance imaging (MRI) and ultrasonography (USG) in predicting the extent of breast residual disease.
 Patients and Methods: patients with stage II-III invasive breast tumor receiving PST and imaged with post-treatment MRI, USG or both were included; deltas were calculated as differences between the longest tumor diameter as measured by MRI and USG and the pathologic size of residual breast tumor. Differences between deltas were tested by using T test for paired data.
 Results: 45 patients treated with PCT in our Institution were eligible. Patients characteristics were as follows: mean age 50 yrs (range 30-70 yrs); stage IIA 31%, IIB 49%, IIIA-B: 20%. Eighty-nine % of the cases had ductal histology, 69% had ER positivity, and 24% had HER2 over-expression. The mean T size at diagnosis was 3.8 cm (range 1.5-8 cm). PCT type was anthracycline-based (24%) or anthracycline-taxane combination (76%). Forty-four patients have been evaluated after PCT by MRI, 41 by USG, 40 patients by both MRI and USG. The mean T size (range) after PCT was 2 cm (0-6.5 cm) and 1.7 cm (0-5 cm) as measured by MRI and USG respectively. The mean interval between breast imaging and surgery was 20 days (range 1-63). Type of surgery was mastectomy in 45% and BCS in 55% of the cases; 6 patients (13%) achieved a pathologic complete response (pCR). The mean pathologic T size was 1.98 cm (range 0-6 cm). The mean of the deltas were 0.04 (SD 1.91) and -0.19 (SD 1.53) for MRI and USG respectively (p=0.22). A complete response by MRI was observed in 9 cases: 3 cases were confirmed as pCRs; 2 cases presented with scattered microscopic residual disease. An USG complete response was observed in 8 cases (4 confirmed pCRs).
 Conclusion: in this series of patients, MRI and USG do not show significant differences in predicting the breast residual tumor after PCT. The major challenge for breast imaging after PCT is represented by scattered residual disease.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4024.

[The family context in end-of-life is a resource to know and support: some reflections]

The family caregiver role is a vital element of home-based patient care. At home, the achievement of the care plan may depend on the physician's relationship with the patient's caregiving network. Caregivers often tolerate an incalculable emotional burden for their work. Although many enjoy a profound sense of benefit and get deep satisfaction in this role, sadness, guilt, anger, resentment, and a sense of inadequacy are also common and understandable reactions. Exhaustion, financial strain, disrupted usual activities, and continuous caregiving contribute to significant mental health morbidity, including anxiety and depression. Early recognition of caregiver distress, help to secure a trusting partnership between the physician and the patient-caregiver unit at the end of life. This paper give some suggestion coming from a decade of support to families during the end stage.

Restoring the balance: harnessing regulatory T cells for therapy in rheumatoid arthritis

Treg play a vital role in the maintenance of tolerance to self antigens, thereby preventing disease through the active suppression of proliferation and pro-inflammatory cytokine production by autoreactive T cells. Here we discuss strategies aimed at enhancing Treg function in patients with rheumatoid arthritis with the ultimate aim of restoring lasting tolerance but without increasing the risk of infections or cancer.

Cells of the synovium in rheumatoid arthritis. B cells

There is significant evidence arising from experimental models that autoantibodies play a key role in the pathogenesis of inflammatory arthritis. In addition to autoantibody production, B cells efficiently present antigen to T cells, produce soluble factors, including cytokines and chemokines, and form B cell aggregates in the target organ of rheumatoid arthritis. In this review we analyze the multifaceted role that B cells play in the pathogenesis of rheumatoid arthritis and discuss how this information can be used to guide more specific targeting of B cells for the therapy of this disease.

If the treatment works, do we need to know why?: the promise of immunotherapy for experimental medicine

There has been much fanfare, and rightly so, heralding a revolution in the treatment of autoimmune disease using biologic agents—antibodies or other molecules that specifically target known mediators of disease. But not all patients respond to even the most successful biologic agent, which may provide clues about alternate disease mechanisms. Studies aimed at understanding the mechanism of action of biologic agents will yield significant benefits for experimental medicine.

Novel suppressive function of transitional 2 B cells in experimental arthritis

The immune system contains natural regulatory cells important in the maintenance of tolerance. Although this suppressive function is usually attributed to CD4 regulatory T cells, recent reports have revealed an immunoregulatory role for IL-10-producing B cells in the context of several autoimmune diseases including collagen-induced arthritis. In the present study, we attribute this suppressive function to a B cell subset expressing high levels of CD21, CD23, and IgM, previously identified as transitional 2-marginal zone precursor (T2-MZP) B cells. T2-MZP B cells are present in the spleens of naive mice and increase during the remission phase of arthritis. Following adoptive transfer to immunized DBA/1 mice, T2-MZP B cells significantly prevented new disease and ameliorated established disease. The suppressive effect on arthritis was paralleled by an inhibition of Ag-specific T cell activation and a reduction in cells exhibiting Th1-type functional responses. We also provide evidence that this regulatory subset mediates its suppression through the secretion of suppressive cytokines and not by cell-to-cell contact. The ability to regulate an established immune response by T2-MZP B cells endows this subset of B cells with a striking and previously unrecognized immunoregulatory potential.

Atorvastatin restores Lck expression and lipid raft-associated signaling in T cells from patients with systemic lupus erythematosus

Loss of tolerance to self-Ags in patients with systemic lupus erythematosus (SLE), a prototypic autoimmune disease, is associated with dysregulation of T cell signaling, including the depletion of total levels of lymphocyte-specific protein kinase (Lck) from sphingolipid-cholesterol-enriched membrane microdomains (lipid rafts). Inhibitors of 3-hyroxy-3-methylgluteryl CoA reductase (statins) can modify the composition of lipid rafts, resulting in alteration of T cell signaling. In this study, we show that atorvastatin targets the distribution of signaling molecules in T cells from SLE patients, by disrupting the colocalization of total Lck and CD45 within lipid rafts, leading to a reduction in the active form of Lck. Upon T cell activation using anti-CD3/anti-CD28 in vitro, the rapid recruitment of total Lck to the immunological synapse was inhibited by atorvastatin, whereas ERK phosphorylation, which is decreased in SLE T cells, was reconstituted. Furthermore, atorvastatin reduced the production of IL-10 and IL-6 by T cells, implicated in the pathogenesis of SLE. Thus, atorvastatin reversed many of the signaling defects characteristic of SLE T cells. These findings demonstrate the potential for atorvastatin to target lipid raft-associated signaling abnormalities in autoreactive T cells and provide a rationale for its use in therapy of autoimmune disease.

Anti-TNF-alpha therapy induces a distinct regulatory T cell population in patients with rheumatoid arthritis via TGF-beta

The induction of regulatory T (T reg) cells holds considerable potential as a treatment for autoimmune diseases. We have previously shown that CD4⁺CD25^hi T reg cells isolated from patients with active rheumatoid arthritis (RA) have a defect in their ability to suppress proinflammatory cytokine production by CD4⁺CD25⁻ T cells. This defect, however, was overcome after anti–tumor necrosis factor (TNF)-α antibody (infliximab) therapy. Here, we demonstrate that infliximab therapy gives rise to a CD4⁺CD25^hiFoxP3⁺ T reg cell population, which mediates suppression via transforming growth factor (TGF)-β and interleukin 10, and lacks CD62L expression, thereby distinguishing this T reg cell subset from natural T reg cells present in healthy individuals and patients with active RA. In vitro, infliximab induced the differentiation of CD62L⁻ T reg cells from CD4⁺CD25⁻ T cells isolated from active RA patients, a process dependent on TGF-β. In spite of the potent suppressor capacity displayed by this CD62L⁻ T reg cell population, the natural CD62L⁺ T reg cells remained defective in infliximab-treated patients. These results suggest that anti–TNF-α therapy in RA patients generates a newly differentiated population of T reg cells, which compensates for the defective natural T reg cells. Therefore, manipulation of a proinflammatory environment could represent a therapeutic strategy for the induction of T reg cells and the restoration of tolerance.

Haematological parameters in elite rugby players during a competitive season

We assessed haematological parameters and possible modifications in elite rugby players throughout a competitive season for increasing the knowledge of physiological characteristics of these sportsmen. Blood samples were collected from the members of the Italian National rugby team at four consecutive training camps during a whole competitive season. Forty-four athletes were recruited for the first camp, 36 for the second, 30 for the third and 32 for the fourth. Due to turnover of the subjects during the season only 13 athletes could be examined at all four camps, and another six in the first three camps. Therefore, we selected the data of these 19 athletes. Iron and transferrin saturation were stable, whilst ferritin increased at the end of the season. The modifications of the soluble transferrin receptor (sTFR) were linked to those of haematocrit: sTFR increased after training and during the competition period when haemoglobin and haematocrit decreased, and decreased at the end of the season. Haemoglobin and haematocrit showed slightly higher levels during the first part of the season and decreased in the second half, when physical demand was high, as demonstrated by biochemical additional tests. Leucocytes and platelets were stable throughout the season. Haematological and iron metabolism parameters in the elite rugby players examined during a whole season fall within physiological range of values. The variability of the parameters during the season is related to training and competition workload. Reticulocytes and sTFR are the most sensitive parameters for studying the iron metabolism of the athletes.

Atorvastatin inhibits autoreactive B cell activation and delays lupus development in New Zealand black/white F1 mice

Systemic lupus erythematosus is a multisystem autoimmune disease characterized by a wide range of immunological abnormalities that underlie the loss of tolerance. In this study we show that administration of atorvastatin to lupus-prone NZB/W F(1) mice resulted in a significant reduction in serum IgG anti-dsDNA Abs and decreased proteinuria. Histologically, the treatment was associated with reduced glomerular Ig deposition and less glomerular injury. Disease improvement was paralleled by decreased expression of MHC class II on monocytes and B lymphocytes and reduced expression of CD80 and CD86 on B lymphocytes. Consequent upon this inhibition of Ag presentation, T cell proliferation was strongly impaired by atorvastatin in vitro and in vivo. A significant decrease in MHC class II expression was also observed in the target organ of lupus disease (i.e., the glomerulus). Serum cholesterol in atorvastatin-treated lupus mice fell to the level found in young NZB/W mice before disease onset. This is the first demonstration that atorvastatin can delay the progression of a spontaneous autoimmune disease and may specifically benefit patients with systemic lupus erythematosus.

Natural serum IgM maintains immunological homeostasis and prevents autoimmunity

Natural (i.e. low-affinity, preimmune) IgM has a wide range of actions in the immune system. That IgM is important in defence against infection has been recognised for many years but recently, due to the generation of mouse models specifically deficient in serum IgM, other functions of serum IgM have been revealed. The participation of natural IgM in autoimmunity has been a subject of speculation for some time, but there is recent definitive evidence that demonstrates its protective role. This review focuses on these new areas of research, which also show that many pathologies not normally recognised as having an immunological basis are modulated by serum IgM.

Type I IFN protects permissive macrophages from Legionella pneumophila infection through an IFN-gamma-independent pathway

Legionella pneumophila is an intracellular pathogen whose replication in macrophages is mainly controlled by IFN-gamma. Freshly isolated peritoneal macrophages elicited in vivo with thioglycolate (TG) from A/J mice are highly permissive to L. pneumophila growth in vitro, while TG-elicited macrophages from CD1 mice are resistant. In this study, we show that when CD1 TG-macrophages are cultured for 7 days, they become permissive to Legionella infection. We demonstrate that treatment with type I IFN (IFN-alphabeta) totally inhibits the growth of L. pneumophila in both freshly isolated A/J and in vitro-aged CD1 TG-macrophages. IFN-alphabeta protective effect on permissive macrophages was comparable to that induced by IFN-gamma. Even low doses of either IFN-alpha or IFN-beta alone were effective in inhibiting L. pneumophila multiplication in macrophage cultures. Notably, treatment of resistant, freshly isolated CD1 TG-macrophages with Ab to mouse IFN-alphabeta significantly enhanced their susceptibility to Legionella infection in vitro, thus implying a role of endogenous IFN-alphabeta in mediating the natural resistance of macrophages to L. pneumophila infection. Finally, addition of anti-IFN-gamma-neutralizing Ab did not restore Legionella growth in IFN-alpha- or IFN-beta-treated A/J or CD1 permissive macrophages, indicating that IFN-alphabeta effect was not mediated by IFN-gamma. This observation was further confirmed by the finding that IFN-alphabeta was effective in inhibiting L. pneumophila replication in macrophages from IFN-gamma receptor-deficient mice. Taken together, our results provide the first evidence for a role of IFN-alphabeta in the control of L. pneumophila infection in mouse models of susceptible macrophages and suggest the existence of different pathways for the control of intracellular bacteria in macrophages.

Compromised function of regulatory T cells in rheumatoid arthritis and reversal by anti-TNFalpha therapy

Regulatory T cells have been clearly implicated in the control of disease in murine models of autoimmunity. The paucity of data regarding the role of these lymphocytes in human autoimmune disease has prompted us to examine their function in patients with rheumatoid arthritis (RA). Regulatory (CD4⁺CD25⁺) T cells isolated from patients with active RA displayed an anergic phenotype upon stimulation with anti-CD3 and anti-CD28 antibodies, and suppressed the proliferation of effector T cells in vitro. However, they were unable to suppress proinflammatory cytokine secretion from activated T cells and monocytes, or to convey a suppressive phenotype to effector CD4⁺CD25⁻ T cells. Treatment with antitumor necrosis factor α (TNFα; Infliximab) restored the capacity of regulatory T cells to inhibit cytokine production and to convey a suppressive phenotype to “conventional” T cells. Furthermore, anti-TNFα treatment led to a significant rise in the number of peripheral blood regulatory T cells in RA patients responding to this treatment, which correlated with a reduction in C reactive protein. These data are the first to demonstrate that regulatory T cells are functionally compromised in RA, and indicate that modulation of regulatory T cells by anti-TNFα therapy may be a further mechanism by which this disease is ameliorated.

Canonical pathway of nuclear factor kappa B activation selectively regulates proinflammatory and prothrombotic responses in human atherosclerosis

Nuclear factor kappa B (NF-kappa B) activation has been observed in human atherosclerotic plaques and is enhanced in unstable coronary plaques, but whether such activation has a protective or pathophysiological role remains to be determined. We addressed this question by developing a short-term culture system of cells isolated from human atherosclerotic tissue, allowing efficient gene transfer to directly investigate signaling pathways in human atherosclerosis. We found that NF-kappa B is activated in these cells and that this activity involves p65, p50, and c-Rel but not p52 or RelB. This NF-kappa B activation can be blocked by overexpression of I kappa B alpha or dominant-negative I kappa B kinase (IKK)-2 but not dominant-negative IKK-1 or NF-kappa B-inducing kinase, resulting in selective inhibition of inflammatory cytokines (tumor necrosis factor alpha, IL-6, and IL-8), tissue factor, and matrix metalloproteinases without affecting the antiinflammatory cytokine IL-10 or tissue inhibitor of matrix metalloproteinases. Our results demonstrate that the canonical pathway of NF-kappa B activation that involves p65, p50, c-Rel, and IKK-2 is activated in human atherosclerosis and results in selective up-regulation of major proinflammatory and prothrombotic mediators of the disease.

Down-regulation of Th1-mediated pathology in experimental arthritis by stimulation of the Th2 arm of the immune response

OBJECTIVE

To assess whether systemic administration of recombinant interferon-gamma (rIFN gamma), a proinflammatory cytokine that influences the differentiation of naive T cells into Th1 cells, promotes the induction of arthritis in DBA/1 mice immunized with type II collagen (CII) in Freund's incomplete adjuvant (IFA) and to determine the antiarthritic effect of treatment with CII in IFA.

METHODS

DBA/1 mice were immunized with CII in IFA and injected intraperitoneally with rIFN gamma (8,000 units/mouse/day) or with recombinant interleukin-12 (rIL-12; 100 ng/mouse/day). In another experiment, mice were immunized with CII in Freund's complete adjuvant (CFA) and treated with a single dose of CII in IFA on the day of immunization or on the day of disease onset. Mice were monitored to assess the effect of the treatment on the severity of disease. Th1/Th2 cytokines and anti-CII antibodies were measured by enzyme-linked immunosorbent assay.

RESULTS

The administration of rIL-12 or rIFN gamma to mice immunized with CII in IFA restored the Th1 response and resulted in the development of arthritis. We then determined whether immunization with CII in IFA had the capacity to prevent and/or ameliorate collagen-induced arthritis. A single intraperitoneal injection of CII in IFA prevented arthritis when given at the time of immunization with CII in CFA and reduced disease severity when given at the time of arthritis onset. The administration of CII in IFA resulted in a profound down-regulation of IFN gamma production and an up-regulation of IL-10 in cultures of draining lymph node cells.

CONCLUSION

These findings demonstrate that it is possible to deflect an ongoing pathogenic Th1 response to an antigen by reimmunization of the same antigen with a Th2-polarizing adjuvant.